New approach to drug delivery in ophthalmological practice: development of composite ophthalmological solution for drug loading of soft contact lenses

Introduction. This article provides a tentative justification of use of soft contact lenses as a carrier of ophthalmological solutions to eye tissues. Aim. The aim of the research is to develop the composition of the ophthalmic transport system for the treatment of glaucoma. Also, the proposed manufacturing algorithms were proposed for drug loading ophthalmological solutions. Materials and methods. Preparation of sodium hyaluronate solution was carried out based on the methodology described in EP 7.0 [01/2011:1472] (Sodium hyaluronate). Results and discussion. The conducted investigation with the purpose to justify a concentration of sodium hyaluronate helped to determine its concentration that gives the viscosity level as close to the upper limit stated in Russian Pharmacopoeia as possible. Buffer solution was chosen with criteria to use as less components in ophthalmological solution as possible. Also, it was found out that the more components are added to the viscous solution, the more viscosity level is decreased. Thus, initial viscosity of solution containing sodium hyaluronate was 149.59 mm2/s, and after addition of active pharmaceutical substance it dropped down to 88.49 mm2/s and 81.36 mm2/s for model solution number 1 and 2, respectively. After addition of citric acid and disodium hydrophosphate, the viscosity of model solution was found to be 78.11 mm2/s and 75.28 mm2/s for model solution number 1 and 2, respectively. Conclusion. As a result of the studies, two alternative model compositions of an ophthalmic solution for the saturation of soft contact lenses for the treatment of glaucoma were proposed. The choice of active pharmaceutical substances, and excipients has been justified. Technological procedure of preparation of model solution was described and explained, where the most attention was paid on dissolving of sodium hyaluronate in purified water. © Naplekov D. K., Zhilyakova E. T., Malyutina A. Yu., Bondarev A. V., Demina N. B., Novikov O. O., Abramovich R. A., 2020.